Turning acid mine water into award-winning municipal water

A shortage of water may be the next crisis facing South Africa. Studies show that water reserves are rapidly depleting with experts predicting that the demand for water in the country will outstrip supply by as soon as 2025.

The Emalahleni Water Reclamation Plant

Although mining accounts for a comparatively low 3% of South Africa’s water withdrawals, it has a significant role to play in driving efficiencies in this area. Anglo American continuously strives to achieve responsible water stewardship, including recycling as much water as is possible a measure to mitigate the strain on the country’s water resources.

In coal mining specifically, water supply is fundamental, particularly in keeping dust levels down. With nine of Coal SA’s ten collieries situated in the water-challenged Mpumalanga coalfields, the company has implemented a range of initiatives to preserve this critical resource.

This includes the construction and operation of the eMalahleni Water Reclamation Plant. 'eMalahleni', as it is known, can claim the accolade of being the only mining initiative to be endorsed by the United Nations Framework Convention on Climate Change (UNFCCC) Momentum for Change Initiative at COP 17 in 2011.

Themba Mkhwanazi, Chief Executive Officer of Coal South Africa said, "The eMalahleni Water Reclamation plant was designed with sustainability in mind. It takes into account the remaining 20 to 25 year life of contributing mines, and will cater for post-closure liabilities. Ultimately it will help address long-term climate adaptation risks and promote a sustainable future for the region, providing better flexibility and self-sufficiency in terms of water usage, not only for the mines but for the surrounding communities in which we operate."

The plant effectively addresses operational challenges resulting from rising mine water levels and recycling polluted water into the environment.

The plant currently meets around 12% of the water-stressed local municipality’s water requirements through the supply of 16 million litres a day into the Municipal reticulation system.

Water is purified to potable quality by reverse osmosis and is then sent on for use by various nearby Anglo American mines and to the eMalahleni Local Municipality. The plant currently meets around 12% of the water-stressed local municipality’s water requirements through the supply of 16 million litres a day into the Municipal reticulation system.

To date, the eMalahleni Water Reclamation Plant has treated in excess of 70 billion litres of water, 50 billion of which have been sent to the municipality with the rest reused within Anglo American’s coal operations.

Contributing mines include Anglo American’s Landau, Greenside and Kleinkopje collieries, as well as South32’s defunct South Witbank mine. Together these mines currently supply up to 30 million litres of water to the plant on a daily basis. This capacity is on track to be increased to 50 million litres a day through the current construction of Phase II of the facility.

Through the use of eMalahleni, Anglo American’s Coal SA business has been able to commit to achieving an overall saving of 11.2% by 2020 through tough but realistic target setting.

Further to the use of the plant, Coal South Africa has implemented Anglo American’s Water Efficiency Target Tool (WETT) to help its mines forecast future water demands as well as identify, prioritise and register savings on projects across working areas and through the production cycle.

The reverse-osmosis plant

The extension to the reclamation water plant

“The theme for this year’s World Water Week is Water for Development, and this reminds us that we have a responsibility to ensure water security for our operations without compromising water resources for other users.  If the demands on a limited resource are growing then we have to use what is available more efficiently,” added Themba.

Click here to download the paper OPERATING AND MAINTENANCE EXPERIENCE AT THE EMALAHLENI WATER RECLAMATION PLANT by Bruce Hutton, Irfaan Kahan, Thubendran Naidu and Peter Gunther.